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authorAlex Lam S.L <alexlamsl@gmail.com>2017-12-27 07:40:34 +0800
committerGitHub <noreply@github.com>2017-12-27 07:40:34 +0800
commitf30790b11bb9e162a19d7769ab54d8bb3f61cc27 (patch)
tree8d247107c9e87383d189aececce75b980c9e7fc4
parent5205dbcbf4f522f8b4dc9f9f9727b621982c9f28 (diff)
downloadtracifyjs-f30790b11bb9e162a19d7769ab54d8bb3f61cc27.tar.gz
tracifyjs-f30790b11bb9e162a19d7769ab54d8bb3f61cc27.zip
fix `dead_code` on `return` assignments (#2668)
fixes #2666
-rw-r--r--lib/compress.js22
-rw-r--r--test/compress/dead-code.js27
2 files changed, 48 insertions, 1 deletions
diff --git a/lib/compress.js b/lib/compress.js
index c8cddc37..bd61b87f 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -4841,15 +4841,17 @@ merge(Compressor.prototype, {
var ASSIGN_OPS = [ '+', '-', '/', '*', '%', '>>', '<<', '>>>', '|', '^', '&' ];
var ASSIGN_OPS_COMMUTATIVE = [ '*', '|', '^', '&' ];
OPT(AST_Assign, function(self, compressor){
+ var def;
if (compressor.option("dead_code")
&& self.left instanceof AST_SymbolRef
- && self.left.definition().scope === compressor.find_parent(AST_Lambda)) {
+ && (def = self.left.definition()).scope === compressor.find_parent(AST_Lambda)) {
var level = 0, node, parent = self;
do {
node = parent;
parent = compressor.parent(level++);
if (parent instanceof AST_Exit) {
if (in_try(level, parent instanceof AST_Throw)) break;
+ if (is_reachable(def)) break;
if (self.operator == "=") return self.right;
return make_node(AST_Binary, self, {
operator: self.operator.slice(0, -1),
@@ -4891,6 +4893,24 @@ merge(Compressor.prototype, {
}
}
}
+
+ function is_reachable(def) {
+ var reachable = false;
+ var find_ref = new TreeWalker(function(node) {
+ if (reachable) return true;
+ if (node instanceof AST_SymbolRef && node.definition() === def) {
+ return reachable = true;
+ }
+ });
+ self.right.walk(new TreeWalker(function(node) {
+ if (reachable) return true;
+ if (node instanceof AST_Scope) {
+ node.walk(find_ref);
+ return true;
+ }
+ }));
+ return reachable;
+ }
});
OPT(AST_Conditional, function(self, compressor){
diff --git a/test/compress/dead-code.js b/test/compress/dead-code.js
index 591dd3a9..7ea380d2 100644
--- a/test/compress/dead-code.js
+++ b/test/compress/dead-code.js
@@ -828,3 +828,30 @@ issue_2597: {
}
expect_stdout: "PASS"
}
+
+issue_2666: {
+ options = {
+ dead_code: true,
+ }
+ input: {
+ function f(a) {
+ return a = {
+ p: function() {
+ return a;
+ }
+ };
+ }
+ console.log(typeof f().p());
+ }
+ expect: {
+ function f(a) {
+ return a = {
+ p: function() {
+ return a;
+ }
+ };
+ }
+ console.log(typeof f().p());
+ }
+ expect_stdout: "object"
+}